Apparatus, system and method for in-line additive manufacturing nozzle inspection

ABSTRACT

An additive manufacturing apparatus, system, and method. More particularly, the disclosed in-line nozzle inspection apparatus, system and method are suitable to monitor an additive manufacturing print nozzle, and may include: at least one sensor integrated with a motion driver for the print nozzle; a plurality of imaging lenses suitable to provide a substantially complete field of view at least about a tip of the print nozzle; and a comparative engine suitable to compare the field of view state to an acceptable state of the print nozzle, and to execute a cleaning of the print nozzle if the field of view state is unacceptable.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application claims benefit to International ApplicationPCT/US2019/066924, filed Dec. 17, 2019, entitled: “Apparatus, System andMethod for In-Line Additive Manufacturing Nozzle Inspection,” whichclaims priority U.S. Provisional Application No. 62/782,430, filed Dec.20, 2018, entitled: “Apparatus, System and Method for In-Line AdditiveManufacturing Nozzle Inspection,” the entirety of which is incorporatedherein by reference as if set forth in its entirety.

BACKGROUND Field of the Disclosure

The present disclosure relates to additive manufacturing, and, morespecifically, to an apparatus, system and method for in-line additivemanufacturing print nozzle inspection.

Description of the Background

Additive manufacturing, including three dimensional printing, hasconstituted a very significant advance in the development of not onlyprinting technologies, but also of product research and developmentcapabilities, prototyping capabilities, and experimental capabilities,by way of example. Of available additive manufacturing (collectively “3Dprinting”) technologies, fused deposition of material (“FDM”) printingis one of the most significant types of 3D printing that has beendeveloped.

FDM is an additive manufacturing technology that allows for the creationof 3D elements on a layer-by-layer basis, starting with the base, orbottom, layer of a printed element and printing to the top, or last,layer via the use of, for example, heating and extruding thermoplasticfilaments into the successive layers. Simplistically stated, an FDMsystem includes a print head which feeds the print material filamentthrough a heated nozzle to print, an X-Y planar control for moving theprint head in the X-Y plane, and a print platform upon which the base isprinted and which moves in the Z-axis as successive layers are printed.

More particularly, the FDM printer nozzle heats the thermoplastic printfilament received to a semi-liquid state, and deposits the semi-liquidthermoplastic in variably sized beads along the X-Y planar extrusionpath plan provided for the building of each successive layer of theelement. The printed bead/trace size may vary based on the part, oraspect of the part, then-being printed. Further, if structural supportfor an aspect of a part is needed, the trace printed by the FDM printermay include removable material to act as a sort of scaffolding tosupport the aspect of the part for which support is needed. Accordingly,FDM may be used to build simple or complex geometries for experimentalor functional parts, such as for use in prototyping, low volumeproduction, manufacturing aids, and the like.

However, the use of FDM in broader applications, such as medium to highvolume production, is severely limited due to a number of factorsaffecting FDM, and in particular affecting the printing speed, quality,and efficiency for the FDM process. As referenced, in FDM printing it istypical that a thermoplastic is extruded, and is heated and pushedoutwardly from a heating nozzle, under the control of the X-Y and/or Zdriver of a print head, onto either a print plate/platform or a previouslayer of the part being produced. More specifically, the nozzle is movedabout by the robotic X-Y planar adjustment of the print head inaccordance with a pre-entered geometry, such as may be entered into aprocessor as a print plan to control the robotic movements to form thepart desired.

As both the nozzle and the print environment may be heated, and thenozzle is subjected to repeated high-speed movement, non-uniform heatingof the nozzle and the print material may occur. Likewise, non-uniformheating within the print nozzle itself may occur. Yet further, movementof the nozzle may, in some instances, cause printing defects, such asstringing or clumping on the nozzle tip.

All of the foregoing adverse circumstances may cause clogging of thenozzle or buildup on the nozzle. Clogging and buildup may havesignificant adverse effects on a print run, may fall into the printbuild, or may force the cessation of a printing altogether.

Notwithstanding the aforementioned adverse effects of nozzle clogging orbuildup on a print run, most FDM printers do not clean the print tip, inspite of the high likelihood of clogging and/or occluding, for thereasons discussed throughout, during particular types of print runs. Ofcourse, a few industrial printers do run a tip cleaning routine atpredetermined intervals in an effort to clear any buildup of debris fromthe print nozzle tip. However, these limited solutions are very timeconsuming (up to 50% of processing time in many cases), and suffer frombeing open loop processes. The open loop nature of such processesdisadvantageously allows for the buildup of debris on the print nozzlebetween the open-loop selected cleaning intervals.

The material that may build up on the nozzle tip is obviously exposed tothe nozzle temperature for a long duration, and thus, in addition toclogging, may burn, which further impedes the expected nozzle flow rate.During nozzle movement on the same layer, in which the nozzle is to stopprinting and then restart after the movement, this nozzle buildup mayooze, or cause unintended print ooze, from the nozzle. The foregoing mayadd to the mis-formation of a layer, a feature, and/or stringing thatare detrimental effects of print nozzle buildup and clogging.

SUMMARY

An additive manufacturing apparatus, system, and method are disclosed.More particularly, the disclosed in-line nozzle inspection apparatus,system and method are suitable to monitor an additive manufacturingprint nozzle, and may include: at least one sensor integrated with amotion driver for the print nozzle; a plurality of imaging lensessuitable to provide a substantially complete field of view at leastabout a tip of the print nozzle; and a comparative engine suitable tocompare the field of view state to an acceptable state of the printnozzle, and to execute a cleaning of the print nozzle if the field ofview state is unacceptable.

BRIEF DESCRIPTION OF THE DRAWINGS

The disclosed non-limiting embodiments are discussed in relation to thedrawings appended hereto and forming part hereof, wherein like numeralsindicate like elements, and in which:

FIG. 1 is an illustration of an additive manufacturing printer;

FIG. 2 is an illustration of an exemplary additive manufacturing system;

FIG. 3 illustrates an in-line print nozzle inspection system;

FIG. 4 illustrate machine vision algorithms;

FIG. 5 illustrate lensing systems for an in-line print nozzle inspectionsystem; and

FIG. 6 illustrates an exemplary computing system

DETAILED DESCRIPTION

The figures and descriptions provided herein may have been simplified toillustrate aspects that are relevant for a clear understanding of theherein described apparatuses, systems, and methods, while eliminating,for the purpose of clarity, other aspects that may be found in typicalsimilar devices, systems, and methods. Those of ordinary skill may thusrecognize that other elements and/or operations may be desirable and/ornecessary to implement the devices, systems, and methods describedherein. But because such elements and operations are known in the art,and because they do not facilitate a better understanding of the presentdisclosure, for the sake of brevity a discussion of such elements andoperations may not be provided herein. However, the present disclosureis deemed to nevertheless include all such elements, variations, andmodifications to the described aspects that would be known to those ofordinary skill in the art.

Embodiments are provided throughout so that this disclosure issufficiently thorough and fully conveys the scope of the disclosedembodiments to those who are skilled in the art. Numerous specificdetails are set forth, such as examples of specific components, devices,and methods, to provide a thorough understanding of embodiments of thepresent disclosure. Nevertheless, it will be apparent to those skilledin the art that certain specific disclosed details need not be employed,and that embodiments may be embodied in different forms. As such, theembodiments should not be construed to limit the scope of thedisclosure. As referenced above, in some embodiments, well-knownprocesses, well-known device structures, and well-known technologies maynot be described in detail.

The terminology used herein is for the purpose of describing particularembodiments only and is not intended to be limiting. For example, asused herein, the singular forms “a”, “an” and “the” may be intended toinclude the plural forms as well, unless the context clearly indicatesotherwise. The terms “comprises,” “comprising,” “including,” and“having,” are inclusive and therefore specify the presence of statedfeatures, integers, steps, operations, elements, and/or components, butdo not preclude the presence or addition of one or more other features,integers, steps, operations, elements, components, and/or groupsthereof. The steps, processes, and operations described herein are notto be construed as necessarily requiring their respective performance inthe particular order discussed or illustrated, unless specificallyidentified as a preferred or required order of performance. It is alsoto be understood that additional or alternative steps may be employed,in place of or in conjunction with the disclosed aspects.

When an element or layer is referred to as being “on”, “engaged to”,“connected to” or “coupled to” another element or layer, it may bedirectly on, engaged, connected or coupled to the other element orlayer, or intervening elements or layers may be present, unless clearlyindicated otherwise. In contrast, when an element is referred to asbeing “directly on,” “directly engaged to”, “directly connected to” or“directly coupled to” another element or layer, there may be nointervening elements or layers present. Other words used to describe therelationship between elements should be interpreted in a like fashion(e.g., “between” versus “directly between,” “adjacent” versus “directlyadjacent,” etc.). Further, as used herein the term “and/or” includes anyand all combinations of one or more of the associated listed items.

Yet further, although the terms first, second, third, etc. may be usedherein to describe various elements, components, regions, layers and/orsections, these elements, components, regions, layers and/or sectionsshould not be limited by these terms. These terms may be only used todistinguish one element, component, region, layer or section fromanother element, component, region, layer or section. Terms such as“first,” “second,” and other numerical terms when used herein do notimply a sequence or order unless clearly indicated by the context. Thus,a first element, component, region, layer or section discussed belowcould be termed a second element, component, region, layer or sectionwithout departing from the teachings of the embodiments.

FIG. 1 is a block diagram illustrating an exemplary filament-basedprinter 100. In the illustration, the printer includes an X-Y axisdriver 102 suitable to move the print head 104, and thus the printnozzle 106 on the print head 104, in a two dimensional plane, i.e.,along the X and Y axes, responsive to the print plan 1190. Furtherincluded in the printer 100 for additive manufacturing are theaforementioned print head 104, including print nozzle 106.

As is evident from FIG. 1, printing may occur upon the flow of heatedprint material outwardly from the nozzle 106 along a Z axis with respectto the X-Y planar movement of the X-Y driver 102. Thereby, layers ofprinted material 110 may be provided from the nozzle 106 onto the printbuild plate 111 along a path dictated by the X-Y driver 102.

More particularly, filament-based 3D printers include an extruding printhead 104 that uses the hobs 103 to move the filament 110 into the heatednozzle 106, i.e., past heater 105 about nozzle 106, at a feed rate tiedto the controller 1100 executing the print plan algorithm 1190 via theX-Y-Z axis driver 102. A motor 109 is generally used to drive at leastone of the hobs 103, such as against an undriven one of the hobs 103.This extrusion and X-Y-Z movements are made responsive to the print plan1190 executed by controller 1100, and are herein included in theadditive manufacturing kinematics.

FIG. 2 illustrates with greater particularity a print head 104 havingnozzle 106 for an exemplary additive manufacturing device, such as a 3-Dprinter, such as a FDM printer. As illustrated, the print material 110is extruded via hobs 103 of the head 104 from a spool of print material110 a into and through the heated nozzle 106, and thus past heater 105,responsively to print plan 1190. More particularly, as the nozzle 106heats the print material 110, the print material is at least partiallyliquefied for output from an end port/tip 106 a of the nozzle at a pointalong the nozzle distal from the print head 104 onto the print build111. Thereby, the extruded material is “printed” outwardly from the port106 a via the Z axis along a X-Y planar path determined by the X-Ydriver (see FIG. 1) connectively associated with the print head 104.

The embodiments optimize the timing of nozzle tip cleaning, such thatthe cleaning occurs when needed, but does not take up significantamounts of process time. The foregoing may be accomplished using variousdifferent methodologies.

For example, an upward mounted process camera may be placed near a tipcleaning station. Thereby, when a cleaning algorithm implemented by theoverall processing system instructs a cleaning of the nozzle tip 106 a,rather than cleaning the nozzle, the nozzle tip 106 a may be moved overthe upward looking camera to allow for a vision inspection of the nozzletip. If the nozzle evidences a need for cleaning, the algorithminstructs the implementation of a cleaning, and, if no need for cleaningis evidenced, printing resumes. The aforementioned embodiment saves thecycle time of tip cleaning when such cleaning is unnecessary. However,to the extent the need for cleaning arises between inspection cycletimes, the foregoing embodiment may miss the existence of the need untilthe next inspection cycle occurs.

In an additional embodiment, and as illustrated in FIG. 3, an in-lineinspection system 200 may include an inspection tool 202, such as acamera, integrated onto the print nozzle system, which is used, at leastin part, to elect when the print nozzle 106 is moved to a cleaningstation 222, such as by the X-Y driver 102. By way of example, thecamera 202 may be integrated on the X-Y driver 102, such that the nozzle106/nozzle tip 106 a may be subject to continuous/real time orsubstantially continuous/real time monitoring by the camera 202 asinstructed by print process algorithm 1190.

In short, algorithm 1190 may include a machine vision algorithm 1190 ato be executed by process controller 1100. Machine vision 1190 a enablescontroller 1100 to actuate and monitor the camera 202 to inspect,evaluate and identify the need to clean the nozzle tip 106 a asevidenced in still or moving images. The machine vision 1190 a may, inconjunction with camera 202 and controller 1100, provide automatic imagecapturing, evaluation and processing capabilities.

Two principle methodologies of machine vision algorithm 1190 a may beeffectuated pursuant to the embodiments. As illustrated in FIG. 4A,subtractive visioning 1190 a-1 may compare an average or optimal“template” vision 302 of the tip to the current vision 304 of the tip.An optimal or maximum variance 306 between the compared images may bepreset in algorithm 1190 a-1, and, when the template vision 302 issubtracted from the current vision 304, a variance in excess of thepredetermined maximum allowable variance 306 is indicative of a need toclean the tip, i.e., in such a case, the variance in the images isindicative of clogging or buildup at the nozzle tip.

In conjunction with subtractive visioning, image alignment 310 may beperformed by visioning algorithm 1190 a-1. That is, a “key” 320 may belocated and aligned as between the template image 302 and the currentimage 304, such that the comparison of the images may be performed at aprecise location and angle. In short, the template and the currentimages may be algorithmically moved/rotated by algorithm 1190 a toprecisely fit the two images atop one another to allow for thesubtraction on, for example, a pixel-by-pixel basis.

Additionally and alternatively, feature visioning 1190 a-2 may beemployed, as illustrated in FIG. 4B. In this methodology 1190 a-2, onlycertain measurements 402 a or features from a current image 304 arecompared with the same specific features or measurements 402 b in aknown acceptable nozzle tip vision. By way of example, only reflectivityor color 402 a of aspects of the nozzle tip may be compared using thismethodology to assess a need for nozzle tip cleaning.

Accordingly, feature visioning may be employed without the need foralignment referenced above in subtractive visioning. However, it shouldbe noted that, contrary to subtractive visioning, feature visioning maynot allow for a pinpointing of the location on the nozzle tip of thebuildup or clog, but such a pinpointing may be unnecessary if an overallcleaning is to be executed by the cleaning algorithm 1190 a regardlessof the location of the clog/buildup once the nozzle exceeds the allowedvariance.

In accordance with the foregoing embodiments, the time delay between atip issue arising, and detection of that tip issue, may be minimal. Thatis, the sensing of a tip issue may occur in real time/substantially realtime. Thus, the execution of a tip cleaning may also occur substantiallycontemporaneously with the occurrence of a tip issue.

More specifically, FIGS. 5A and 5B illustrate an exemplary hardwarelayout suitable to enable the real time nozzle tip sensing discussedabove in FIG. 3, and the application of the algorithms 1190 a to enablereal time nozzle cleaning as discussed in FIGS. 4A and 4B. Asillustrated in FIGS. 5A and 5B, one or more lensing systems 502 mayenable the sensing of one or more aspects of the nozzle by a singlesensor/camera 202.

In FIG. 5A, a 3-way reflective lensing system 502 allows for the viewingof all portions of a nozzle by a single camera 202, such as may bemounted on the X-Y print head driver 102 as referenced above. Morespecifically, a main reflector lens 504 may include three dedicatedreflective features, one to provide a primary reflection 504 a from anaspect of the nozzle, and at least two other reflective lens portions504 b, c to receive a primary reflection from other reflective lenses506 such that two secondary reflections may be provided to the camera202, and thereby a 360 degree view of the nozzle may be provided to thecamera 202 by lensing system 502. The reflectors may be known lenses ormirrors, polished metallic reflectors, or the like. FIG. 5B more clearlyillustrates the 360 degree field of view provided in accordance with theexemplary embodiment of FIG. 5A.

Thus, although the varying views provided in the embodiments above mayhave differing perspective geometries, the use of subtractive or featurevisioning may allow that exact dimensioning or image scaling is notcritical, although the visioning algorithm 1190 a may require knowledgeof relevant angles/distances of the lensing system used.

It should additionally be noted that the lensing and imaging systemsdiscussed herein throughout are inherently present within the printenvironment in ones of the disclosed embodiments. As such, and becausetemperatures within a print build area may reach or exceed 200 degreesC., the disclosed sensing and lensing hardware in the build area must besuitable to survive and operate at such typical build area temperatures.

FIG. 6 depicts an exemplary computing system 1100 for use as thecontroller 1100 in association with the herein described systems andmethods. Computing system 1100 is capable of executing software, such asan operating system (OS) and/or one or more computingapplications/algorithms 1190, such as applications/algorithms includingand applying the print plan and the nozzle inspection/cleaningalgorithms 1190 a discussed herein throughout.

The operation of exemplary computing system 1100 is controlled primarilyby computer readable instructions, such as instructions stored in acomputer readable storage medium, such as hard disk drive (HDD) 1115,optical disk (not shown) such as a CD or DVD, solid state drive (notshown) such as a USB “thumb drive,” or the like. Such instructions maybe executed within central processing unit (CPU) 1110 to cause computingsystem 1100 to perform the operations discussed throughout. In manyknown computer servers, workstations, personal computers, and the like,CPU 1110 is implemented in an integrated circuit called a processor.

It is appreciated that, although exemplary computing system 1100 isshown to comprise a single CPU 1110, such description is merelyillustrative, as computing system 1100 may comprise a plurality of CPUs1110. Additionally, computing system 1100 may exploit the resources ofremote CPUs (not shown), for example, through communications network1170 or some other data communications means.

In operation, CPU 1110 fetches, decodes, and executes instructions froma computer readable storage medium, such as HDD 1115. Such instructionsmay be included in software such as an operating system (OS), executableprograms, and the like. Information, such as computer instructions andother computer readable data, is transferred between components ofcomputing system 1100 via the system's main data-transfer path. The maindata-transfer path may use a system bus architecture 1105, althoughother computer architectures (not shown) can be used, such asarchitectures using serializers and deserializers and crossbar switchesto communicate data between devices over serial communication paths.System bus 1105 may include data lines for sending data, address linesfor sending addresses, and control lines for sending interrupts and foroperating the system bus. Some busses provide bus arbitration thatregulates access to the bus by extension cards, controllers, and CPU1110.

Memory devices coupled to system bus 1105 may include random accessmemory (RAM) 1125 and/or read only memory (ROM) 1130. Such memoriesinclude circuitry that allows information to be stored and retrieved.ROMs 1130 generally contain stored data that cannot be modified. Datastored in RAM 1125 can be read or changed by CPU 1110 or other hardwaredevices. Access to RAM 1125 and/or ROM 1130 may be controlled by memorycontroller 1120. Memory controller 1120 may provide an addresstranslation function that translates virtual addresses into physicaladdresses as instructions are executed. Memory controller 1120 may alsoprovide a memory protection function that isolates processes within thesystem and isolates system processes from user processes. Thus, aprogram running in user mode may normally access only memory mapped byits own process virtual address space; in such instances, the programcannot access memory within another process' virtual address spaceunless memory sharing between the processes has been set up.

In addition, computing system 1100 may contain peripheral communicationsbus 135, which is responsible for communicating instructions from CPU1110 to, and/or receiving data from, peripherals, such as peripherals1140, 1145, and 1150, which may include printers, keyboards, and/or thesensors, encoders, and the like discussed herein throughout. An exampleof a peripheral bus is the Peripheral Component Interconnect (PCI) bus.

Display 1160, which is controlled by display controller 1155, may beused to display visual output and/or presentation generated by or at therequest of computing system 1100, responsive to operation of theaforementioned computing program. Such visual output may include text,graphics, animated graphics, and/or video, for example. Display 1160 maybe implemented with a CRT-based video display, an LCD or LED-baseddisplay, a gas plasma-based flat-panel display, a touch-panel display,or the like. Display controller 1155 includes electronic componentsrequired to generate a video signal that is sent to display 1160.

Further, computing system 1100 may contain network adapter 1165 whichmay be used to couple computing system 1100 to external communicationnetwork 1170, which may include or provide access to the Internet, anintranet, an extranet, or the like. Communications network 1170 mayprovide user access for computing system 1100 with means ofcommunicating and transferring software and information electronically.Additionally, communications network 1170 may provide for distributedprocessing, which involves several computers and the sharing ofworkloads or cooperative efforts in performing a task. It is appreciatedthat the network connections shown are exemplary and other means ofestablishing communications links between computing system 1100 andremote users may be used.

Network adaptor 1165 may communicate to and from network 1170 using anyavailable wired or wireless technologies. Such technologies may include,by way of non-limiting example, cellular, Wi-Fi, Bluetooth, infrared, orthe like.

It is appreciated that exemplary computing system 1100 is merelyillustrative of a computing environment in which the herein describedsystems and methods may operate, and does not limit the implementationof the herein described systems and methods in computing environmentshaving differing components and configurations. That is to say, theconcepts described herein may be implemented in various computingenvironments using various components and configurations.

In the foregoing detailed description, it may be that various featuresare grouped together in individual embodiments for the purpose ofbrevity in the disclosure. This method of disclosure is not to beinterpreted as reflecting an intention that any subsequently claimedembodiments require more features than are expressly recited.

Further, the descriptions of the disclosure are provided to enable anyperson skilled in the art to make or use the disclosed embodiments.Various modifications to the disclosure will be readily apparent tothose skilled in the art, and the generic principles defined herein maybe applied to other variations without departing from the spirit orscope of the disclosure. Thus, the disclosure is not intended to belimited to the examples and designs described herein, but rather is tobe accorded the widest scope consistent with the principles and novelfeatures disclosed herein.

What is claimed is:
 1. An in-line nozzle inspection system suitable tomonitor an additive manufacturing print nozzle, comprising: at least onesensor integrated with a motion driver for the print nozzle; a pluralityof imaging lenses suitable to provide a substantially complete field ofview at least about a tip of the print nozzle; and a comparative enginesuitable to compare the field of view state to an acceptable state ofthe print nozzle, and to execute a cleaning of the print nozzle if thefield of view state is unacceptable.
 2. The in-line nozzle inspectionsystem of claim 1, wherein the at least one sensor comprises at leastone camera.
 3. The in-line nozzle inspection system of claim 1, whereinthe sensor comprises an optical sensor.
 4. The in-line nozzle inspectionsystem of claim 1, wherein the sensor comprises a reflectivity sensor.5. The in-line nozzle inspection system of claim 1, wherein theintegration comprises a physical mount.
 6. The in-line nozzle inspectionsystem of claim 1, wherein the print nozzle comprises solely the tip ofthe print nozzle.
 7. The in-line nozzle inspection system of claim 1,wherein the plurality of imaging lenses comprises three imaging lenses.8. The in-line nozzle inspection system of claim 1, wherein ones of theimaging lenses comprise indirect reflective lenses.
 9. The in-linenozzle inspection system of claim 1, wherein ones of the imaging lensescomprise direct reflective lenses.
 10. The in-line nozzle inspectionsystem of claim 1, wherein the substantially complete field of viewcomprises a 360 degree field of view.
 11. The in-line nozzle inspectionsystem of claim 1, wherein the acceptable state comprises a templateimage.
 12. The in-line nozzle inspection system of claim 11, wherein thecomparison comprises a substractive comparison to the template image.13. The in-line nozzle inspection system of claim 12, wherein thesubtractive comparison comprises a maximum variance from the templateimage.
 12. The in-line nozzle inspection system of claim 12, wherein thesubtractive comparison comprises an optimum variance from the templateimage.
 13. The in-line nozzle inspection system of claim 1, wherein theacceptable state comprises a feature characteristic of the print nozzle.14. The in-line nozzle inspection system of claim 13, wherein thecomparison comprises a feature characteristic comparison.
 15. Thein-line nozzle inspection system of claim 1, further comprising acleaning station.
 16. The in-line nozzle inspection system of claim 15,wherein the execution of the cleaning comprises a movement by the motiondriver of the print nozzle into the cleaning station.
 17. The in-linenozzle inspection system of claim 15, wherein the cleaning stationcleans clogs of the print nozzle.
 18. The in-line nozzle inspectionsystem of claim 15, wherein the cleaning station cleans buildup from theprint nozzle.
 19. The in-line nozzle inspection system of claim 1,wherein the print nozzle comprises a FDM print nozzle.
 20. The in-linenozzle inspection system of claim 1, wherein the motion driver operatesin three axes.